Generalizability of empirical correlations for predicting higher heating values of biomass

Designing efficient biomass energy systems requires a thorough understanding of the physicochemical, thermodynamic, and physical properties of biomass. One crucial parameter in assessing biomass energy potential is the higher heating value (HHV), which quantifies its energy content. Conventionally, HHV is determined through bomb calorimetry, but this method is limited by factors such as time, accessibility, and cost. To overcome these limitations, researchers have proposed a diverse range of empirical correlations and machine-learning approaches to predict the HHV of biomass based on proximate and ultimate analysis results. The novelty of this research is to explore the universal applicability of the developed empirical correlations for predicting the Higher Heating Value (HHV) of biomass. To identify the best empirical correlations, nearly 400 different biomass feedstocks were comprehensively tested with 45 different empirical correlations developed to use ultimate analysis (21 different empirical correlations), proximate analysis (16 different empirical correlations) and combined ultimate-proximate analysis (8 different empirical correlations) data of these biomass feedstocks. A quantitative and statistical analysis was conducted to assess the performance of these empirical correlations and their applicability to diverse biomass types. The results demonstrated that the empirical correlations utilizing ultimate analysis data provided more accurate predictions of HHV compared to those based on proximate analysis or combined data. Two specific empirical correlations including coefficients for each element (C, H, N) and their interactions (C*H) demonstrate the best HHV prediction with the lowest MAE (~0.49), RMSE (~0.64), and MAPE (~2.70%). Furthermore, some other empirical correlations with carbon content being the major determinant also provide good HHV prediction from a statistical point of view; MAE (~0.5–0.8), RMSE (~0.6–0.9), and MAPE (~2.8–3.8%)

Catalytic Conversion of Glycerol to Bio-Based Aromatics

Green application of biodiesel-derived glycerol will boost biodiesel production in terms of sustainability and economics. The glycerol to liquid fuels is a promising route that provides an additional energy source, which contributes significantly to energy transition besides biodiesel. This pathway could generate alkyl-aromatic hydrocarbons with a yield of ∼60%, oxygenates, and gases. MFI Zeolites (H-ZSM-5) catalysts are mainly used to propagate the aromatization pathway. This chapter presents the pathways, challenges, catalytic design, influences of catalyst acidity, metal addition, reaction condition, and catalysts deactivation on glycerol conversion to hydrocarbon fuels and aromatics. Studies revealed that time on stream, temperature, and weight hourly space velocity (range of 0.1–1 h−1) influences the benzene, toluene, and xylene BTX and benzene, toluene, ethylbenzene, and xylene BTEX yield. Acidity of the H-ZSM-5 could be tailored by metals, additives, and binders. Bronsted acidity promotes coke formation which results in reversible deactivation of the H-ZSM-5 catalyst. It is hoped that this study will promote intensified research on the use of glycerol for purposes of fuel generating and valuable products

Multi-criteria decision analysis for the evaluation and screening of sustainable aviation fuel production pathways

The aviation sector, a significant greenhouse gas emitter, must lower its emissions to alleviate the climate change impact. Decarbonization can be achieved by converting low-carbon feedstock to sustainable aviation fuel (SAF). This study reviews SAF production pathways like hydroprocessed esters and fatty acids (HEFA), gasification and Fischer–Tropsch Process (GFT), Alcohol to Jet (ATJ), direct sugar to hydrocarbon (DSHC), and fast pyrolysis (FP). Each pathway's advantages, limitations, cost-effectiveness, and environmental impact are detailed, with reaction pathways, feedstock, and catalyst requirements. A multi-criteria decision framework (MCDS) was used to rank the most promising SAF production pathways. The results show the performance ranking order as HEFA > DSHC > FP > ATJ > GFT, assuming equal weight for all criteria

Pathways for the Valorization of Animal and Human Waste to Biofuels, Sustainable Materials and Value-Added Chemicals

Human and animal waste, including waste products originating from human or animal digestive systems such as urine, feces, and animal manure, have constituted a nuisance to the environment. Inappropriate disposal and poor sanitation of human and animal waste often cause negative impacts on human health through contamination of the terrestrial environment, soil, and water bodies. Therefore, it is necessary to convert these wastes into useful resources to mitigate their adverse environmental effect. The present study provides an overview and research progress of different thermochemical and biological conversion pathways for the transformation of human- and animal-derived waste into valuable resources. The physicochemical properties of human and animal waste are meticulously discussed as well as nutrient recovery strategies. In addition, a bibliometric analysis is provided to identify the trends in research and knowledge gaps. The results reveal that the U.S.A, China and England are the dominant countries in the research areas related to resource recovery from human or animal waste. In addition, researchers from the University of Illinois, the University of California Davis, the Chinese Academy of Science and Zhejiang University are front runners in research related to these areas. Future research should be centred on developing technologies for the on-site recovery of resources, exploring integrated resource recovery pathways, and exploring different safe waste processing methods

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Waste tires based biorefinery for biofuels and value-added materials production

Waste tires are a distinct type of waste material that is produced in large quantities. These tires present a significant environmental challenge due to their high toxicity and flammability, as well as their persistence and the difficulty of storing or processing them. Every year, approximately 1.4 billion waste tires are produced, and they typically end up either in landfills or being incinerated, exacerbating these environmental problems. However, waste tires are also a promising source of energy and energetic materials, thanks to their low moisture content, heterogeneous nature, and high heating value. Waste tires are comprised of various materials, including carbon black, fabric, filler, antioxidants, natural rubber, and steel wire, all in different compositions. This study provides an in-depth analysis of the various methods for converting waste tires into biofuels, green chemicals, and innovative materials for energy and environmental applications. The study specifically includes a bibliometric analysis to examine the current research trends, identify knowledge gaps, and explore prospects for waste tire biorefinery. Additionally, a comparative assessment of various traditional strategies for managing waste tires is discussed. The study proposes a new integrated waste tire biorefinery that incorporates multiple methods for the valorization of waste tires, including alternative pathways for integrating thermochemical and biological processes. Bibliometric analysis shows that the frequently used keywords in waste tire-related research include pyrolysis, crumb rubber, recycling, combustion, and activated carbon

The Infusion of Gamification in Promoting Chemical Engineering Laboratory Classes

Active learning strategies are increasingly implemented in chemical engineering education, yet challenges persist in stimulating student participation and motivation. The rigorous demands placed on students in this field, from complex practical requirements to extensive programming and computational skills, underscore the need for innovative educational tools. Gamification emerges as a pivotal instrument in this context, fostering active student engagement, enhancing practical application of knowledge, increasing motivation, and providing a more precise assessment of student comprehension. These educational games serve as a powerful adjunct to traditional teaching strategies, equipping students with necessary skills for their future careers in the field. These games include laboratory course games, process simulators, games used in foundational courses, and those centered around reaction kinetics. This entry primarily investigates the various games employed to bolster student learning during chemical engineering laboratory courses. A thorough analysis is conducted on the survey of existing games used specifically in chemical engineering labs. The gamut of games discussed includes escape games, along with Virtual Reality (VR) and Augmented Reality (AR) games, all aiming to enhance laboratory experiences in areas such as fluid mechanics, organic reactions, and process control. This entry concludes by examining the prospective trajectory of gamification in chemical engineering labs, offering insights into future potential and advancements in this innovative educational approach